Method of producing horns for gramophones and the like.



E. NIER. METHOD OF PRODUCING HORNS FOB. GRAMOPHONES AND THE LIKE.

APPLIOATION FILED JAN. 3, 1912.

Patented Sept. 17, 1912.

cuwmnm I'LANOGRAPH C0-.\VAS|IINGTON. n. c.

UNITED STATES PATENT OFFICE.

ERNST NIER, OF BEIERFELD, GERMANY.

METHOD OF PRODUCING HORNS FOR GRAMOPHONES AND THE LIKE.

To all whom it may concern: I

Be it known that I, ERNST NIER, a subject of the German Emperor,residing at Beierfeld, in Saxony, Germany, haveinvented a certain newand useful Improve ment in the Method of Producing Horns for Gramophonesand the Like, of which the following is a specification.

The method heretofore adapted for the manufacture of trumpet-mouthedhorns for gramophones, phonographs and the like, consists in joiningtogether a plurality of suitably shaped pieces, by means of lap joints,rivets or the like. This method of manufacture has the disadvantage thatthe jointed pieces are capable of independent vibration, whichdeteriorates the purity of the sound. The process of tightening up oneof the joints, by hammering or similar means, always tends to loosen theother joints, so that a certain amount of looseness of structure isinevitable.

The object of the present invention is to obviate this disadvantage, andthe invention consists in the improved method of manufacture which willnow be described with reference to the accompanying drawing.

In the drawing, Figures 1, 2 and 3 are sectional views illustratingthree successive stages of the manufacture of a horn. Fig. 4 is a rearelevation of a finished horn, and Fig. 5 is a longitudinal section of afinished horn, with dotted lines indicating the shape of the wall atsuccessive stages of manufacture.

A suitably shaped strip of the material of which the horn is to be madeis bent into the shape of a hollow truncated cone, and the contactingedges are joined together by means of a lap joint or the like. A verytight joint can be made in this case by hammering or other suit-abletreatment, and there are no other joints liable to be loosened by thistreatment. The smooth sides of the hollow truncated cone formed in themanner described are indicated at k in Fig. 5. The rim at the base ofthe cone may be bent and curled around in the usual manner, as shown inthe drawing. The next step in the process of manufacture consists inmaking longitudinal indentations in the cone, that is to sayindentations which extend in the direction of generators of the cone, asindicated at a in Figs. 1 and 5. These indentations, which arepreferably uniformly spaced apart, increase in depth Specification ofLetters latent.

Application filed January 3, 1912.

Patented Sept. 17 1912.

Serial No. 669,222.

from their ends toward their central parts, so that the conical body isconstricted at the middle, and acquires the shape indicated by thedotted line 70 in Fig. 5. The said indentations may be made inwardinstead of outward, as shown in the drawing. In on der to increase theconstriction referred to, the Walls of the ribs formed by theindentations a are bent together so that their lower edges 6 and 0 closetogether; by this means a series of tubular ribs d is formed on the hornbody. This bending together of the rib walls is not essential to theinvention, but enables a considerable constriction to be obtained with acomparatively small number of ribs.

The ribs cZ may be retained in tubular shape, or may be flattened out byhammering or pressing, as shown in Fig. 3, so that the horn acquires thefinal shape shown at k in Fig. 5.

Instead of flattening the ribs (1 symmetrically, as shown in thedrawing, they may be bent over and flattened down sidewise, to the rightor left of the oint made by the edges 5 and c.

WVhat I claim as my invention and desire to secure by Letters Patent ofthe United States is 1.The method of manufacturing a trumpet mouthedhorn for a gramophone or the like by bending a sheet of metal to theshape of a hollow truncated cone, securing the side edges together andmaking longitudinal indentations in the sides of said cone, increasingin depth from each of their ends toward their central parts and curvingthe metal inward between the largest and smallest diameter of said cone.

2. The method of manufacturing a trumpet mouthed horn for a gramophoneor the like by bending a sheet of metal to the shape of a hollowtruncated cone, securing the side edges together and making longitudinalindentations in the sides of said cone, increasing in depth from each oftheir ends toward their central parts and curving the metal inwardbetween the largest and smallest diameter of said cone, and bendingtogether the walls of the several indentations, so that the indentationsare converted into tubular ribs tapering to zero at each end.

3. The method of manufacturing a trumpet mouthed horn for a gramophoneor the like by bending a sheet of metal to the shape of a hollowtruncated cone, securing the ribs tapering to zero at each end and fiat-10 S1Cl6 edges together and making longltudlnal tenlng the said tubularrlbs. lndentatlons in the sldes of said cone, in In witness whereof Ihave signed thls creasing in depth from each of their ends specificationin the presence of two wittoward their central parts and curving thenesses. metal inward between the largest and small- ERNST NIER. estdiameter of said cone, bending together Witnesses:

OTTO SPRUY L,

the walls of the several indentations so that RUDOLPH FRICKE.

the indentations are converted into tubular "Copies of this patent maybe obtained for five cents each, by addressing-the Commissioner ofPatents,

Washington, D. 10.

